Electrochemical wastewater treatment equipment for advanced wastewater treatment.

I. Product Overview

Advanced wastewater treatment refers to the subsequent purification process used to remove residual COD, ammonia nitrogen, color, suspended solids, and characteristic pollutants from effluent after conventional secondary treatment (biological or physicochemical treatment) to meet stricter discharge standards or reuse requirements. With the continuous upgrading of wastewater discharge standards, advanced treatment has become a rigid requirement in many wastewater treatment systems.

The challenge of advanced treatment lies in the fact that the pollutants remaining in the effluent after biological treatment are stubborn organic compounds that are difficult to biodegrade—including humic acid, fulvic acid, lignin derivatives, residual dyes and intermediates, polycyclic aromatic hydrocarbons, and antibiotic residues. Although the concentration of these substances is not high, their stable structure and strong chemical inertness make them difficult to remove effectively by conventional methods.

Traditional advanced treatment methods each have their limitations:

Activated carbon adsorption:Effective at adsorbing stubborn organic matter, but it only "transfers" rather than "eliminates" it; saturated carbon becomes hazardous waste, and regeneration costs are high.

Fenton oxidation:Strong oxidizing power, but requires the addition of large amounts of H₂O₂ and Fe²⁺, producing large amounts of iron sludge (hazardous waste), and has high operating costs.

Membrane separation (UF/RO):Can retain pollutants in concentrated water, but produces 20%–30% high-concentration concentrated water, requiring further treatment.

This system uses electrochemical oxidation technology, installed after a biological system or conventional physicochemical treatment as an advanced treatment unit, precisely oxidizing and attacking stubborn organic matter in the biological effluent. Through direct anodic oxidation and electrocatalysis-generated hydroxyl radicals (·OH) and other strong oxides, residual COD, ammonia nitrogen, and color that cannot be removed by conventional processes are thoroughly mineralized or decomposed.

The entire process consumes only electricity, does not introduce chemical agents, and does not produce sludge or concentrated water. It operates at normal temperature and pressure, making it an ideal end-of-pipe unit for wastewater upgrading and advanced treatment.

II.Difficulties in advanced wastewater treatment and solutions with this equipment

III. Working Principle

The effluent from the biochemical system or conventional physicochemical treatment enters the electrochemical reactor for deep purification under the action of electrodes:

(1) Deep oxidation of persistent organic matter (deep COD removal)

The COD remaining in the biochemical effluent is mostly structurally stable, recalcitrant organic matter—humic acids, fulvic acids, lignin derivatives, polycyclic aromatic hydrocarbons, long-chain alkanes, residual dye molecules, etc. These substances are almost not utilized by microorganisms in a conventional biochemical environment (B/C < 0.05).

In the electrochemical reactor: Some organic matter loses electrons directly on the anode surface and is oxidized, destroying the stable molecular structure. Hydroxyl radicals (·OH) attack stubborn organic matter non-selectively with their strong oxidizing power, causing aromatic rings to open, long carbon chains to break, and heterocycles to decompose. Chloride ions in the wastewater are electrolyzed to generate active chlorine, which replenishes the oxidation of residual organic matter. Stubborn organic matter → ring opening/chain breaking → organic acids/alcohols/aldehydes → further mineralization into CO₂ + H₂O.

(2) Deep removal of residual ammonia nitrogen Residual ammonia nitrogen in biochemical effluent is removed through an indirect oxidation pathway: Chloride ions are electrolyzed at the anode to generate active chlorine, which rapidly oxidizes ammonia nitrogen into nitrogen gas.

(3) Deep removal of color The color in biochemical effluent mainly comes from dye residues with stable chromophore structures, lignin derivatives, and humic substances. Under electrochemical action, these chromophores: Unsaturated conjugated structures (—N=N—, quinone types, conjugated double bonds, etc.) are oxidized and broken, resulting in completely colorless and transparent effluent. The effluent is colorless, transparent, odorless, and sterile.

IV. Core Advantages (for advanced wastewater treatment)

V. Technical Parameters (Customizable)

VI . Process Location

Option 1: Advanced Treatment of Biological Effluent

Secondary biological treatment (A/O, A²/O, SBR, MBR, etc.) → Secondary sedimentation tank → Electrochemical advanced treatment unit → Discharge meeting standards/Reuse for production

Description: The electrochemical equipment is directly installed at the downstream end of the biological system to treat recalcitrant residual COD, ammonia nitrogen, and color in the biological effluent. This is the most standard advanced treatment configuration, suitable for upgrading municipal wastewater treatment plants, industrial park wastewater treatment plants, and various industrial wastewater treatment plants. The original biological system requires no modification; only an advanced treatment unit is added at the downstream end, resulting in a small engineering workload, controllable investment, and quick results.

Option 2: Further Upgraded Discharge Standards

Biological effluent → Conventional advanced treatment (meeting existing standards) → Electrochemical purification unit → Effluent meeting stricter standards → Discharge to sensitive water bodies or reuse